Synthesis of Biobased Block Copolymers Using A Novel Methacrylated Methyl Salicylate and Poly(3-Hydroxybutyrate)

A novel biobased vinyl monomer was synthesized by the reaction of methyl salicylate with methacrylic anhydride. The resulting salicylate based monomer was polymerized by reversible addition fragmentation transfer (RAFT) polymerizations using two or three trithiocarbonate functionalized poly(3-hydroxybutyrate) macro agents. The molecular structures of the obtained polymers were confirmed by NMR spectroscopy and GPC analysis. The resulting block copolymers showed glass transition temperature (Tg) at 5 °C and melting temperature (Tm) at 160 °C according to DSC results. Compared to PHB, the obtained block copolymers displayed enhanced thermal stability according to TGA results. The overall rate constants of the RAFT polymerization using tri-functionalized PHB macro agent were determined as 2.58 ×10−4, 1.17×10−4, and 0.50×10−4 L mol−1s−1 for 70, 80 and 90 °C, respectively. The activation energy was found to be 18.6 kcal K−1mol−1. The overall rate constant of the homopolymerization of the obtained monomer was determined as 1.14×10−4 Lmol−1s−1